Apparatus for refining oils



Nov. 15, 1938. B, AY ET AL 2,137,214

APPARATUS FOR REFINING OILS Filed Dec. 28, A1937 Patented Nov. 15, 1938 APPARATUS FOR REFINING OILS Benjamin Clayton, Houston, Tex., and Walter B. Kerrick, Los Angeles, and Henry M. Stadt, Glendale, Calif., assig'nors to Refining, Inc., Reno, Nev., a corporation of Nevada Application December 28, 1937, Serial No. 182,124

6 Claims.

This invention relates to an improved apparatus for refining oils, and more particularly vegetable, animal and certain other oils capable of separation and refining. The invention is particularly adaptable to the refining of glyceride-type oils which contain free fatty acids, by treating such oils with an aqueous solution of an alkaline reagent capable of neutralizing said free fatty acids. It is well known that oils of this type readily respond to treatment in this manner, the free fatty acids being converted into soap which, with other impurities tending to contaminate the desired refined oil, collect in small masses to form foots.

- The principal object of the invention is to reduce the time period in the separation of the various constituents of oils, such as the foots from cottonseed and similar oils.

Another object is to more completely recover the more valuable constituents.

Another object is to promote the maximal separation by the addition of the minimal quantity of chemical reagents.

Another object is to minimize the conversion or transformation of the natural constituents of the oil by prolonged internal reactions.

Another object is to conserve all of the colloidal values in the oil in removing the solids therefrom.

Another object is to preserve and clarify'the natural colors, flavors, odors, and other values desirable in commercial oil cuts or separations.

Another object is to avoid oxidation, fermentation, decomposition and other natural reactions incidental to the prolonged and involved operations heretofore practiced in this art.

Another object is to isolate and remove certain constituents present in some edible oils, such as the red coloring matter in cottonseed oil. The above and other valuable results are largely due to the fact that expressed seed oils can .be taken immediately from the press and the whole refining completed in a few minutes before chemical reactions and decompositions set 5 in; in "contradistinction to prior practices requiring longer periods of hours or even days, in some instances.

Other objects and advantages will appear as the description progresses,

- In this specification and the accompanying The following disclosure will relate particularly to the treatment of expressed cottonseed oil, which teaching will guide those skilled in the art in treating other substances, without departing from the spirit of the invention. .5

The whole oil as it comes from the press contains hulls, linters, nitrogenous non-fatty materials such as gums, and the like. The soluble gums, albuminous and other impurities are not truly water soluble, but theyimbibe or absorb 10 water and swell, forming a glutinous sludge in the separator.

A desirable refining solution for alkali refining consists of about twelve percent (12%) of caustic soda in water, of which about one percent 16 to two percent (1% to 2%) is added to the oil by volume for California cottonseed oil.

Figure 1 of the drawing diagrammatically shows a schematic apparatus in accordance with this invention, wherein the whole oil is pumped-from 20 the drip tank A,-through the pipe A to the mixing tank I, and Figure 2 is a fragmentary view similar to Figure 1 showing a modified apparatus.

In employing the apparatus of Fig. 1, the reagent, such as alkali in solution, is mixed with 25 the oil in the tank I, from whence it is pumped into the descending coils 3 by the pump 2. These coils are properly enclosed above the burner 4.

From the coils the oil passes through the thermostatic unit 5, after which it is jetted into the 30 centrifuge 6, through the calibrated nozzle 1. The valve 1 is introduced into the fiowline to manually regulate the amount of back pressure in the coils 3.

The back pressure at the nozzle reacts in the 35 coils against the check valve 8 at the pump, to maintain the predetermined pressure on theoil.

If a pulsating pump is used at 2, it is advisable to insert the air chamber 9 in the line to absorb the pulsations.

The oil passing through the thermostatic unit 5, controls the heat generated at 4, by controlling the throttle valve l0 controlling the fuel passing through the pipe II, to the burner 4.

.In the present apparatus the oil and alkali are maintained in as constant volume or body in the coil 3 as may be. That is, there is no separation of vapors, foaming, or sudden or uneven expansion of the mixture within the apparatus.

The oil is thus treated by a continuous process 50 in small active quantities rather than in large batches.

It will be noted that the liquid after leaving the pump 2 flows in a continuous stream out of contact with the atmosphere through the coil 3 and that the apparatus may be operated continuously overlong periods if the supply of liquid in h perature is increased by the application of heat.

It is desirable that the solution fiow downwardly through the coil 3 toward the source of heat so that the temperature of the solution progressively risestoward the discharge 1 from the heater.

It is important thatthe volume of heat be automatically regulated by the temperature of the solution. The maintained temperature of the oil'can be manually or thermostatically controlled at 5. i

There should be maintained coordination between the constant volume of input, output and the volume of heat applied to maintain the desired pressure in the coils 3. This will establish the proper velocity of the oil within the-coils, to insure the finest division of the alkaliand diffusion of the alkaline solution within the oil. This is assisted by the progressively rising temperature which causes an increased interstitial penetration and improved distribution of the alkali. Every molecule or globule of oil is acted upon by the solution and the inter reactions are complete, as proved in the resultant product.

In the present invention the quantity of excess alkali may be so small that saponificationis greatly reduced and the free oil is not excessively attacked by the alkali.

The heated mixture from the coil 3 is delivered into the centrifuge 6. -Centrifuging this mixture from the heater removes the foots or "soap stock resulting from the alkali treatment accomplished in the calls.

The processed oil may then be clarified or bleached in the agitating tank l0 by the addition of clays or in any other conventional manner.

The clarified oil may then be pumped by means of the pump ll, through the conventional filter press II. The filtered oil drains from the filter press into the tank Hi. The ultimate edible product is a clear, pure, light colored stock, practically free from the deleterious red color, .with the' natural flavor preserved.

In some of the apparatus heretofore employed the whole oil is agitated at high temperature (145 F.) open to the atmosphere, for long periods, about 45 minutes, in the presence of an ex-- cess of alkali; then it often stands for days to permit separation by precipitation. The oil and soap stock are so long in contact during the settling of the oils, that decomposition sets in and new free fatty acids are formed, defeating the purpose intended. The agitation also causes undesirable emulsification.

.When treating certain types of California cottonseed oils the small-quantity of alkaliwhich it' acids which give rise to rancid flavors, odors and the accompanying bacterial reactions.

The present'invention can be simplified and speeded up by accomplishing the mixing by injecting the alkali or alkaline solution into the fiowin'g stream of oil from'the tank A. This is done by introducing the reagent meter l4 into the oil line a. If it is installed at the pump 2 as shown, it canbe geared thereto and the quantity of alkali solution synchronized with the quantity of oil measured by the pump 2.- It is obvious, however, if as shown by the modified apparatus of Figure 2. the alkali is introduced closer to the oil supply A, which may be remote from the heater 3, premixing with the oil will take place in the pipe A before reaching the heater 3.

In this shorter operation the foots" andother heavier constituents comprising the whole oil are put through the heater 3 without oxidation or atmospheric reactions. The nozzle 1 continuously discharges into the centrifuge. Thus, the modified apparatus provides for a process which is truly continuous from the extractor at A to the centrifuge I2. I

The reagent thus pumped into the line A in measured quantity, enters the oil in filamentary form and'performs its previously described reactions. The ultimate result is the same in both.

instances. The particular advantage of the modified apparatus is that the whole separation can be accomplished in a few minutes after the oil is a desirable economy and is superior to reheat-' ing the raw oil after it has chilled. Another advantage of the modified apparatus in which the oil is refined under plus pressure, is that the separated oil emerges from the heater 3, thoroughly sterilized.

Thefoots, etc.,- removed by the centrifuge show practically no free oil and are more easily divided into their constituent gums, resins and inert suspended matter, than when the whole oil is treated by any other apparatus, heretofore employed, so far as we are aware.

It is to be taken into consideration that certain substances contained in animal and vegetable oils and having reactions with acid can be treated by this apparatus with an acid reagent. Processes of refining animal and vegetable oils with acid reagents arewell known in the art and involve the treating of the oil with acids of 'suflicient strength to act uponcoloring matters and impurities other than fatty acids to form the foots and render them separable .from the oil. Thus,' drying oils such as linseed or soya bean oil to be used for certain purposes are treated with from one-half to one and onefourth percent of relatively strong acid, for example, a 60 B. sulfuric acid, to render impurities separable from the oil probably by dehydration or carbonization reactions upon the impurities. Other acids such as hydrochloric acid may be employed and. in either case such acids will also attack the oils as well as impurities therein. Sulfuric acid will sulfonate the oils while hydrochloric acid will chlorinate them. Sulfuric acid is ordinarily used and any sulfonation of the oil isdeleterious, for example, such accomplished in the present apparatus without any reagent. In this operation the foots containing gums, resins, coloring materials, etc.,

- which are present in animal and vegetable oils,

are agglomerated or coalesced by the heat present in the mixture whereby to facilitate ce"trifugal separation thereof.

As an alternative operation in carrying out our broad invention as herein defined, we may preheat the oil before admixture with the refining reagent as shown in the Clayton et al. ap-

plication, Serial No. 685,130, filed August 14,

1933 and now issued as Patent No. 2,100,275 of November 23, 1937. As an example, the oil may be preheated in stream fiow, as shown in said application, to a temperature ranging, for example, from 100 F. to 200 F. depending upon the type of oil, the refining reagent or the prop- 'erties of the refined oil desired. As an operative example, such temperatures ordinarily will range from 120 to 160. The invention, however, is not limited to any precise temperature range.

As a still further form of the broad invention herein disclosed, the mixture of the refined oil and foots may be introduced to a heated centrifugal separator with or without previous heating as shown, for example, in Clayton application, Serial No. 34,258, filed August 1, 1935, and now issued as Patent No. 2,100,277 of November 23, 1937, and Clayton et al. application, Serial No. 678,574, filed July 1, 1933, or the oil may be preheated and .led directly to the heated centrifuge with the refining reagent contacting therewith just before its introduction to the centrifuge or immediately thereafter so that the mixture is heated in the centrifugal to a temperature facilitating the separation.

In any event, the invention may be employed for either complete or partialrefining. By partial refining we mean an operation wherein gums and like foreign materials may be rapidly sep arated and recovered as a valuable by-product and the purified oil conditioned, if desirable, for further refining.

These various forms of the invention are set not substantially below 100 F. to approximately 200 F. depending upon the type of oil being treated and the characteristics desired in the refined oil. The temperature employed is sufficient to break any tight difllcultly separable emulsion which may result from the mixing of the oil and reagent.

This application is a continuation-in-part of our co-pending applications, Serial No. 172,622,-

filed November 3, 1937; Serial No. 756,148, filed December 5, 1934, and Serial No. 534,533, filed It is also a fact that in v May 2, 1931, which matured into Patent No.

What we claim is:

1. An apparatus for the continuous and quick purification of animal and vegetable oils containing free fatty acids comprising in combination a source of supply for the oil and a source of supply for alkaline refining reagent; a mixing chamber; pumping apparatus for pumping including metering devices for feeding proportioned'streams of the reagent and oil through the mixing receptacle where the same are admixed .for a brief period to effect neutralization of said free fatty acids and to form soap stock; a casing enclosing the mixing chamber to exclude air therefrom whereby to prevent the form'ation of'a .difiicultly separable emulsion while the mixture remains in said mixing chamber; a heating device; means for connecting the mixing chamber to the heating device, said means being also closed from the atmosphere whereby the mixture is pumped under super-atmospheric pressure through the heating device, heating means for supplying heat to the heating device to condition the'mixture during its rapid fiow through the heating chamber for the act of centrifugal separation of the soap stock from the v refined oil;' a centrifugal and conduit means for continuously introducing the conditioned mixture to the said centrifugal.

2. An apparatus for the continuous and quick purification of animal and vegetable oils containing free fatty acids comprising in combination a source of supply for the oil anda source of supply for alkaline refining reagent; a mixing chamber; pumping apparatus for pumping including metering devices for feeding proportioned streams of the reagent and oil through the mixing receptacle where the same are admixed for a brief period to effect neutralization of said free fatty acids and to form soap stock; a casing enclosing the mixing chamber to exclude air therefrom whereby to prevent the formation of a diificultly separable emulsion while the mixture remains in said mixing chamber; a heating device; means for connecting the mixing chamber to the heating device, said means being also closed from. the atmosphere whereby the mixture is pumped under super-atmospheric pressure through the heating device, heating means for supplying heat to the heating device to condition the mixture during its rapid flow through the heating chamber for the act of centrifugal separation of the soap stock from the refined oil; a centrifugal and conduit means for continuously introducing the conditioned mixture to the said centrifugal; clarifying apparatus comprising a receptacle for continuously receiving the refined oil from the centrifugal, said clarifying apparatus being constructed and arranged duringthe passage-of the refined oil therethrough to remove the residual impurities re maining'in the oil following centrifugation.

3. An apparatus for the continuous and quick I stock; said mixing device including a casing enclosing the mixing chamber for excluding air therefrom whereby to prevent the formation of a difficultly separable emulsion while the mixthe conditioned mixture thereto.

4. An apparatus for the quick and continuous purification..of animal and vegetable oils which comprises,.'in combination, a relatively small mixing receptacle; .pumping apparatus and metering devices associated therewith for quickly and continuously pumping predetermined proportioned streams of the oil and refining reagent through .said mixing receptacle; means for supplying heat. tOathe mixturein said receptacle sufficient to break "any emulsion which may resuit from the admixture of the oil and refining reagent and. to condition the mixture during its quick and continuous flow for the subsequent act of centrifugally separating the foots from the refined oil; a centrifugal separator; means for continuously feeding the conditioned mixture to the. centrifugal separator and for separating the-footsfrom the refined oil.

5. An apparatus for the quick and continuous refining of animal and vegetable oils containing free fatty acids comprising receptacles for retaining crude vegetable oil and an alkaline refining reagent respectively; a mixing device; pipes for connecting said receptacles to said mixing device; pumping apparatus provided with metering devices for pumping predetermined proportions of the oil and reagent to the mixing device; said mixing device including a case for preventing the ingress of substantial air to the ,mixing device; means, for supplying heat to oppose or break the emulsion resulting from said mixing apparatus and to condition the mixture for centrifugal separation; a centrifugal separator and a passage for continuously and uniformly discharging the conditioned mixture from the mixing device to the centrifugal.

6. An apparatus for the refining of animal and reagent and said oils; a centrifugal separator; a conduit connecting the receptacle with the centrifugal separator; pumping means adapted to discharge a stream of said mixture through said conduit to said centrifugal separator under super atmospheric pressure; heating means, said heating means being constructed and arranged to,

Vegetable oils comprising; in combination, a re- .ceptaclefor receiving an admixture of a refining 

